The way to do this is to set up a 30 degree angle in a coordinate plane in the first quadrant. I say the first quadrant since the first quadrant goes from 0 to 90 degrees and 30 falls right in that interval. Using the positive x-axis as the initial ray of the 30 degree angle and the terminal ray of the angle as the hypotenuse of a right triangle, if we drop a height from the end of the terminal ray to the x-axis we have formed said right triangle. The angle at the origin is the 30 degree angle. According to the Pythagorean triple for a 30-60-90 triangle, the side across from the 30 degree angle measures 1, which is the height of our triangle. The side across from the 60 degree angle is square root of 3, which is the base of our triangle, and the hypotenuse is 2. The cos identity is the ratio that utilizes the side adjacent to the reference angle over the hypotenuse, which for us is

. That's the third choice down. Finding an "exact" value means that they want you to NOT express your answer in decimal form.
E. 8x+7(325)=15(325)
It would include the 8 hrs. of x miles per hour and the 7 hrs. of 325 miles per hour, giving the total miles. Then, as you eliminate, you can find out what (x) is.
36 + x would be your answer. When something is 'increased', you are adding to it. Such as saying 47 increased by -5x is the same as 47 + (-5x).
If this wasn't the answer you were looking for, let me know. For now, I hope this helped:)
I believe the expression would be 7(g)+7
Implicit differentiation
chain rule is important here
I'll show the steps partially




now evaluate for (-2,2)
x=-2 and y=2



that's it, simplest form